柴北缘托莫尔日特地区滩间山群碎屑岩组沉积环境及其地质意义  

Sedimentary Environment and Geological Significance of Clastic Formation from Tanjianshan Group in Tuomoerrite Area,North Qaidam

作　　者：万淑敏 曹俊 王启蒙 Wan Shumin;Cao Jun;Wang Qimeng(School of Earth Sciences,East China University of Technology,Nanchang,Jiangxi 330013;No.1 Geological Exploration Institute,Bureau of Geology and Mineral Resources Exploration and Development of Henan Province,Zhengzhou,Henan 450001)

机构地区：[1]东华理工大学地球科学学院,江西南昌330013 [2]河南省地质矿产勘查开发局第一地质勘查院,河南郑州450001

出　　处：《资源环境与工程》2023年第4期373-382,共10页Resources Environment & Engineering

基　　金：东华理工大学研究生创新基金项目(YC2022-s598)。

摘　　要：柴北缘构造带是中国西北地区重要的多金属成矿带,带内滩间山群因发育以锡铁山为代表的多个金属矿床而备受关注。前人对柴北缘滩间山群火山岩组做过大量的研究,但对碎屑岩组的研究相对薄弱。选取托莫尔日特地区滩间山群碎屑岩组的硅质岩为研究对象,在详细的野外地质调查基础上,开展全岩主量、微量元素分析,讨论硅质岩成因及其沉积环境意义。结果表明,托莫尔日特地区滩间山群硅质岩的SiO_(2)含量为70.39%~82.47%,均值为75.99%,属低硅质硅质岩;Al/(Al+Fe+Mn)值介于0.40~0.80,均值为0.58;∑REE值为22.51×10^(-6)~81.33×10^(-6),均值为41.02×10^(-6);稀土元素北美页岩标准化配分曲线具左倾、弱正Eu异常、弱负Ce异常特征,均指示了硅质岩的热水沉积成因。托莫尔日特地区滩间山群形成时代应为寒武纪—早奥陶世,其中碎屑岩组发育有硅质岩,判断其形成于大陆边缘沉积环境,它们可能代表了一套缺乏陆源碎屑来源、以洋内岛弧为主要沉积物源区的弧前沉积组合。这些特征表明,托莫尔日特地区滩间山群碎屑岩组具有弧前盆地充填物的结构和组成特征。The North Qaidam tectonic belt is an important polymetallic belts in the northwest of China.The Tanjianshan group which developed within the belt have attracted much attention due to the host of several deposits represented by Xitieshan deposit.The Volcanic Formation of Tanjianshan Group have been studied extensively,but the research on the clastic rock group is relatively weak.The siliceous rocks of the Clastic Formation of Tanjianshan Group in the Tomorrit area were selected as the main research object.On the basis of detailed field investigation,the main and trace elements of the whole rock were analyzed,and the genesis of siliceous rocks and their sedimentary environment significance were discussed.The results show that the content of SiO 2 in the siliceous rocks of Tanjianshan Group in Tomorrit area is 70.39%-82.47%,with an average of 75.99%,which belongs to low siliceous siliceous rocks.The Al/(Al+Fe+Mn)values range from 0.40 to 0.80,with an average value of 0.58.The∑REE value is 22.51×10^(-6)-81.33×10^(-6),and the average value is 41.02×10^(-6).The standardized distribution curve of rare earth elements in NASC has the characteristics of left deviation,weak positive Eu anomaly and weak negative Ce anomaly.The above characteristics indicate the hydrothermal sedimentary genesis of siliceous roks.The formation age of Tanjianshan Group in Tuomoerrit area should be Cambrian-Early Ordovician,and the siliceous rocks developed in the Clastic Formation are formed in the sedimentary environment of the continental margin,which may represent a set of forearc sedimentary assemblages without terrigenous clastic sources and with intra-oceanic island arc as the main sedimentary source area.These characteristics indicate that the Clastic Formation of Tanjianshan group in Tomorrit area has the structure and composition characteristics of forearc basin fillings.

关 键 词：滩间山群 硅质岩 岩石地球化学 洋内岛弧 柴北缘 

分 类 号：P588.21[天文地球—岩石学]